责任链之拦截器

ゞ浴缸里的玫瑰 2023-05-29 06:24 42阅读 0赞

### 文章目录 ###

*  责任链
 *  拦截器
 *   *  注册拦截器
     *  往registrations变量添加拦截器
     *  运行步骤
     *  关键代码

# 责任链 #

一种设计模式，它会将对象一个一个进行处理，如果第一个处理不了，会扔到后面的节点进行处理。像拦截器一样，当请求被第一个拦截器拦截之后，后面的拦截器就不用继续拦截了。否则一个接一个进行拦截。

# 拦截器 #

## 注册拦截器 ##

![在这里插入图片描述][watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3dlaXhpbl8zODMzNjY1OA_size_16_color_FFFFFF_t_70]

## 往registrations变量添加拦截器 ##

![在这里插入图片描述][watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3dlaXhpbl8zODMzNjY1OA_size_16_color_FFFFFF_t_70 1]

## 运行步骤 ##

![在这里插入图片描述][watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3dlaXhpbl8zODMzNjY1OA_size_16_color_FFFFFF_t_70 2]  
![在这里插入图片描述][watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3dlaXhpbl8zODMzNjY1OA_size_16_color_FFFFFF_t_70 3]  
![在这里插入图片描述][20191105102253455.png]

## 关键代码 ##

![在这里插入图片描述][watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3dlaXhpbl8zODMzNjY1OA_size_16_color_FFFFFF_t_70 4]

上面这张图尤为重要，像拦截器前致拦截boolean preHandle，为啥是boolean，再这里进行判断。  
其次也是责任链的体现，一个一个拦截器执行，如果中途有一个已经拦截到了，返回false。

![在这里插入图片描述][watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3dlaXhpbl8zODMzNjY1OA_size_16_color_FFFFFF_t_70 5]  
可以看到这个就是我们之前注册的拦截器哦~

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[20191105102253455.png]: https://img-blog.csdnimg.cn/20191105102253455.png
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